Ceiling fans have been around for many years as a useful air circulator. The popular blade style over the years is a flat planar rectangular blade that can have a slight tilt, as shown for example in U.S. Pat. No. Des. 355,027 to Young and U.S. Pat. No. Des. 382,636 to Yang. These patents while moving air are not concerned with maximizing optimum downward airflow. Furthermore, many of the flat ceiling fan blades have problems such as vibrations and wobbling during use, and excessive noise that is noticeable to persons in the vicinity of the fan blades.
Aircraft, marine and automobile engine propeller type blades have been altered over the years to shapes other than flat rectangular. See for example, U.S. Pat. No. 1,903,823 to Lougheed; U.S. Pat. No. 1,942,688 to Davis; U.S. Pat. No. 2,283,956 to Smith; U.S. Pat. No. 2,345,047 to Houghton; U.S. Pat. No. 2,450,440 to Mills; U.S. Pat. No. 4,197,057 to Hayashi; U.S. Pat. No. 4,325,675 to Gallot et al.; U.S. Pat. No. 4,411,598 to Okada; U.S. Pat. No. 4,416,434 to Thibert; U.S. Pat. No. 4,730,985 to Rothman et al. U.S. Pat. No. 4,794,633 to Hickey; 4.844,698 to Gornstein; U.S. Pat. No. 5,114,313 to Vorus; and U.S. Pat. No. 5,253,979 to Fradenburgh et al.; Australian Patent 19,987 to Eather. However, these patents are describing devices that are generally used for high speed water, aircraft, and automobile applications where the propellers are run at high revolutions per minute(rpm) generally in excess of 500 rpm. None of these propellers are designed for optimum airflow at low speeds of less than approximately 200 rpm which is the desired speeds used in overhead ceiling fan systems.
Some alternative blade shapes have been proposed for other types of fans. See for example, U.S. Pat. No. 1,506,937 to Miller; U.S. Pat. No. 2,682,925 to Wosik; U.S. Pat. No. 4,892,460 to Volk; U.S. Pat. No. 5,244,349 to Wang; Great Britain Patent 676,406 to Spencer; and PCT Application No. WO 92/07192.
Miller ""937 requires that their blades have root xe2x80x9clips 26xe2x80x9d FIG. 1 that overlap one another, and would not be practical nor useable for three or more fan blade operation for a ceiling fan. Wosik ""925 describes xe2x80x9cfan blades . . . particularly adapted to fan blades on top of cooling towers such for example as are used in oil refineries and in other industriesxe2x80x9d, column 1, lines 1-5, and does not describe any use for ceiling fan applications. The Volk ""460 patent by claiming to be xe2x80x9caerodynamically designedxe2x80x9d requires one curved piece to be attached at one end to a conventional planar rectangular blade. Using two pieces for each blade adds extreme costs in both the manufacturing and assembly of the ceiling itself. Furthermore, the grooved connection point in the Volk devices would appear to be susceptible to separating and causing a hazard to anyone or any property beneath the ceiling fan itself. Such an added device also has necessarily less than optimal aerodynamic properties.
Wang ""349 requires each of their blades be xe2x80x9cdrilled with a plurality of perforations . . . for reducing weight . . . (and) may be reinforced by at least one rib . . . xe2x80x9d, abstract. Clearly, such a blades would not be aesthetically pleasing to the user to have various holes and ribs visible on the blades, and there is no description for increasing airflow with such an arrangement. Great Britain Patent ""406 describes xe2x80x9cfan impellersxe2x80x9d that require an xe2x80x9ca unitary structure . . . constituted by a boss and four bladesxe2x80x9d page 1, lines 38+, and does not describe any single blades that can be used without any central boss type hub arrangement nor any use for less than three or more than four blade operation that will allow versatility for mounting separate numbers of blades on a ceiling fan motor. PCT ""192 is for use xe2x80x9cin an electric fan . . . to convert axially existing ambient air into a radially outward current of airxe2x80x9d, abstract, and is shown in FIGS. 5-12 as being used for being mounted on xe2x80x9cpost(s)xe2x80x9d, and the like, and is not directed toward a ceiling fan operation, which would direct air primarily downward. Additionally, PCT ""192 generally requires an elaborate arrangement of using plural blades angled both upward and downward for operation.
Thus, the need exists for solutions to the above described problems in the prior art.
The first objective of the subject invention is to provide ceiling fan blades that are aerodynamically optimized to move up to approximately 40% or more air than traditional flat planar ceiling fan blades.
The second objective of the subject invention is to provide ceiling fan blades that are quieter and provide greater comfort than traditional flat planar ceiling fan blades.
The third objective of the subject invention is to provide ceiling fan blades that are less prone to wobble than traditional flat planar ceiling fan blades.
The fourth objective of the subject invention is to provide ceiling fan blades that reduce electrical power consumption and are more energy efficient over traditional flat planar ceiling fan blades.
The fifth objective of the subject invention is to provide ceiling fan blades designed for superior airflow at up to approximately 200 revolutions per minute(rpm).
The sixth objective of the subject invention is to provide ceiling fan blades being more aesthetically appealing than traditional flat planar ceiling fan blades.
Three embodiments of a novel ceiling fan blade are described where each blade can include a tip end having a twist of approximately 5 degrees to approximately 10 degrees, and a root end attached to a ceiling fan motor, wherein the positive twist provides increased air flow over other ceiling fan blades. The root end can include a twist of approximately 20 to approximately 35 degrees. The blades generally include a concave raised bottom and a convex shaped upper surface. The blades are mounted to motor assemblies in a twisted configuration. The blades can be mounted to a ceiling fan motor and provide enhanced airflow at speeds of up to approximately 200 revolutions per minute(rpm). The novel ceiling fan system includes wingspans of up to approximately 52 inches and up to approximately 54 inches.